The former Hibs striker came off the bench to grab what proved to be the winning goal for Murty’s side as they resisted a robust second half display from Ross County and reclaimed second place in the Premiership.
Daniel Candeias gave Rangers a half-time lead with Cummings’ strike providing necessary insurance as County halved the deficit with a late penalty kick. The Highland outfit have now gone 11 league games without a victory and are now six points adrift of relegation rivals Partick Thistle and Hamilton Accies.
County looked every inch a side rooted to the bottom of the table in the first half, their lack of confidence and self-belief glaringly evident from the opening stages. The Dingwall club’s six-year stay in Scotland’s top flight is in serious danger of coming to an end this summer.
Coyle’s side were a bag of nerves defensively and surrendered possession all too often and easily against a Rangers side who needed little encouragement as they looked to build on their progressive form and performances in recent weeks.
Murty’s only complaint about a dominant first half display would have been that his team only had a single goal advantage to show for it.
With January signings Sean Goss and Jamie Murphy again catching the eye, as they had in their debuts against Aberdeen in midweek, the visitors knocked the ball around with good tempo and accuracy to create a steady procession of openings.
County goalkeeper Aaron McCarey, at fault for Candeias’ breakthrough strike, showed signs of vulnerability as early as they second minute when he grasped a shot from the Portuguese winger unconvincingly at the second attempt after initially giving the ball away with a poor kick-out.
The home side weren’t helped by an enforced change in the eighth minute, Christopher Routis suffering a shoulder injury which saw him replaced by Tim Chow.
As Rangers cranked up the pressure, Jason Holt saw a shot headed over his own crossbar by County captain Marcus Fraser and there was another fortunate let-off for the hosts from the resultant corner kick, whipped in by Murphy, as David Bates flicked an effort against a post.
One of many penetrating passes by Goss led to a sight of goal for Murphy, the on-loan Brighton winger’s shot blocked.
Rangers fully merited the 21st minute lead provided by Candeias but it was a goal McCarey should have prevented. The Irish ‘keeper got a hand to the dipping 22-yard shot from Candeias but his timing was badly off as he could only help the ball on its way into the net.
Morelos should have doubled Rangers’ lead six minutes later when he seized upon a wretchedly misplaced pass from County wing-back Kenny van der Weg. The Colombian striker worked his way clear to the edge of the penalty area but pulled his shot wide of McCarey’s left hand post.
McCarey redeemed himself to an extent for his earlier mistake when he made a fine save to keep out a sweetly struck shot from Goss as the on-loan QPR midfielder continued to impressively impose his presence on proceedings.
There was more work for McCarey to do just before the interval and he excelled again to deny a close range header from Murphy who had been picked out by James Tavernier’s cross.
The tone for a more competitive and energetic second half display from County was set by Gardyne as he finally posted his team’s first attempt at goal in the 49th minute. It was a simple save for Wes Foderingham but it signalled a greater level of ambition and purpose from Coyle’s men.
Josh Windass forced McCarey into another smart save when he cut in from the left to curl in a good shot but Rangers found it difficult to rediscover the momentum they had enjoyed in the opening 45 minutes.
They were being forced onto the back foot much more often as County pursued an equaliser. A cross from Jason Naismith caused uncertainty in the Rangers defence and a shot from van der Weg was scrambled clear.
Former Liverpool striker David Ngog introduced, replacing Craig Curran for County as they sought to intensify their attacking threat. They were incensed not to be awarded a penalty in the 71st minute. When Foderingham could only flick another dangerous Naismith cross into the path of Ross Draper, the big midfielder’s header appeared to be handled by Bates as he blocked it in the six yard box. Amid furious protests from the home players, the match officials saw nothing amiss.
Murty looked to revitalise his side with a couple of changes, Greg Docherty making his debut as a replacement for the fading Goss before Cummings came on for the out of touch Morelos.
It was Cummings who made what proved to the decisive contribution of the afternoon, pouncing on a slack ball from Draper and racing through to claim his first goal for Rangers with a low shot which beat McCarey with the aid of a slight deflection off Harry Souttar.
But there was a nervy ending to the contest for the visitors when County were given a penalty in the 90th minute, Russell Martin judged to have handled the ball when he blocked a shot from Ngog at point blank range.
Ngog sent Foderingham the wrong way from the spot, setting up a frantic finale in four minutes of stoppage time but Rangers held on for the victory they needed to jump back above Aberdeen in the Premiership table.
ROSS COUNTY: McCarey, Naismith, Souttar, Routis (Chow 8), Van der Weg; Gardyne, Draper, Fraser, O’Brien, Keillor-Dunn (Schalk 78); Curran (Ngog 55). Subs not used: Fox, Effiong, McKay, Dingwall.
RANGERS: Foderingham, Tavernier, Martin, Bates, John; Holt, Goss (Docherty 74); Candeias (Halliday 84), Windass, Murphy; Morelos (Cummings 79). Subs not used: Alnwick, Herrera, Kranjcar, Cardoso.